1 files changed, 58 insertions, 22 deletions

diff --git a/src/southbridge/intel/lynxpoint/pch.c b/src/southbridge/intel/lynxpoint/pch.c
index c4a3acf8b6..c2765e91eb 100644
--- a/src/southbridge/intel/lynxpoint/pch.c
+++ b/src/southbridge/intel/lynxpoint/pch.c
@@ -113,56 +113,92 @@ static void pch_hide_devfn(unsigned devfn)
 #define IOBP_RETRY 1000
 static inline int iobp_poll(void)
 {
-	unsigned try = IOBP_RETRY;
-	u32 data;
+	unsigned try;
 
-	while (try--) {
-		data = RCBA32(IOBPS);
-		if ((data & 1) == 0)
+	for (try = IOBP_RETRY; try > 0; try--) {
+		u16 status = RCBA16(IOBPS);
+		if ((status & IOBPS_READY) == 0)
 			return 1;
 		udelay(10);
 	}
 
-	printk(BIOS_ERR, "IOBP timeout\n");
+	printk(BIOS_ERR, "IOBP: timeout waiting for transaction to complete\n");
 	return 0;
 }
 
-void pch_iobp_update(u32 address, u32 andvalue, u32 orvalue)
+static u32 pch_iobp_read(u32 address)
 {
-	u32 data;
+	u16 status;
+
+	if (!iobp_poll())
+		return 0;
 
 	/* Set the address */
 	RCBA32(IOBPIRI) = address;
 
 	/* READ OPCODE */
-	RCBA32(IOBPS) = IOBPS_RW_BX;
-	if (!iobp_poll())
-		return;
+	status = RCBA16(IOBPS);
+	status &= ~IOBPS_MASK;
+	status |= IOBPS_READ;
+	RCBA16(IOBPS) = status;
+
+	/* Undocumented magic */
+	RCBA16(IOBPU) = IOBPU_MAGIC;
+
+	/* Set ready bit */
+	status = RCBA16(IOBPS);
+	status |= IOBPS_READY;
+	RCBA16(IOBPS) = status;
 
-	/* Read IOBP data */
-	data = RCBA32(IOBPD);
 	if (!iobp_poll())
-		return;
+		return 0;
 
 	/* Check for successful transaction */
-	if ((RCBA32(IOBPS) & 0x6) != 0) {
-		printk(BIOS_ERR, "IOBP read 0x%08x failed\n", address);
-		return;
+	status = RCBA16(IOBPS);
+	if (status & IOBPS_TX_MASK) {
+		printk(BIOS_ERR, "IOBP: read 0x%08x failed\n", address);
+		return 0;
 	}
 
+	/* Read IOBP data */
+	return RCBA32(IOBPD);
+}
+
+void pch_iobp_update(u32 address, u32 andvalue, u32 orvalue)
+{
+	u16 status;
+	u32 data = pch_iobp_read(address);
+
+	/* WRITE OPCODE */
+	status = RCBA16(IOBPS);
+	status &= ~IOBPS_MASK;
+	status |= IOBPS_WRITE;
+	RCBA16(IOBPS) = status;
+
 	/* Update the data */
 	data &= andvalue;
 	data |= orvalue;
+	RCBA32(IOBPD) = data;
+
+	/* Undocumented magic */
+	RCBA16(IOBPU) = IOBPU_MAGIC;
+
+	/* Set ready bit */
+	status = RCBA16(IOBPS);
+	status |= IOBPS_READY;
+	RCBA16(IOBPS) = status;
 
-	/* WRITE OPCODE */
-	RCBA32(IOBPS) = IOBPS_RW_BX;
 	if (!iobp_poll())
 		return;
 
-	/* Write IOBP data */
-	RCBA32(IOBPD) = data;
-	if (!iobp_poll())
+	/* Check for successful transaction */
+	status = RCBA16(IOBPS);
+	if (status & IOBPS_TX_MASK) {
+		printk(BIOS_ERR, "IOBP: write 0x%08x failed\n", address);
 		return;
+	}
+
+	printk(BIOS_INFO, "IOBP: set 0x%08x to 0x%08x\n", address, data);
 }
 
 /* Check if any port in set X to X+3 is enabled */